* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
a {
    text-decoration: none;
}
ul {
    list-style: none;
}
body {
    color: #eee;
    padding-top: 70px;
}
.nav {
    width: 100%;
    height: 50px;
    line-height: 50px;
    background: #222;
}
.container {
    margin: 0 auto;
    padding: 0 15px;
}
.nav-fix {
    position: fixed;
    left: 0;
    top: 0;
    z-index: 2000;
}
.clearfix::after {
    content: '';
    clear: both;
    display: block;
}
.nav-header {
    background: #222;
    position: relative;
    z-index: 222;
}
.nav-header h2 {
    float: left;
}
.nav-header a {
    float: right;
    color: #eee;
    border: 1px solid #777;
    font-size: 26px;
    height: 30px;
    line-height: 30px;
    margin-top: 10px;
    padding: 0 12px;
}
.nav-list {
    background: #222;
    margin: 0 -15px;
    border-top: 1px solid #999;
    display: none;
} 

.nav-list ul li a{
    color: #eee;
    padding: 10px 15px;
}
.container {
    width: 100%;
}
.bg_img {
    background: url(https://gimg2.baidu.com/image_search/src=http%3A%2F%2Fcdn.duitang.com%2Fuploads%2Fitem%2F201410%2F04%2F20141004172507_J8Mty.jpeg&refer=http%3A%2F%2Fcdn.duitang.com&app=2002&size=f9999,10000&q=a80&n=0&g=0n&fmt=jpeg?sec=1621866379&t=c155999fab116261ee7ecc45480a4b8e) no-repeat center center;
    background-size: cover;    
    height: 500px;
}


/*
  媒体查询
*/
@media screen and (max-width: 767px) {
    .nav-list {
        transform: translateY(-500px);
    }
    .nav-list.active {
        transform: translateY(0);
        transition: all .3s ease-in-out;
        display: block;
    }
    /* .nav-list.hidden {
        transition: all .2s ease-in-out;
    } */
}
@media screen and (min-width: 768px) {
    .container {
        width: 750px;
    }
    .nav-header h2, .nav-header a {
        display: none;
    }
    .nav-list {
        display: block;
        font-size: 14px;
    }
    .nav-list ul {
        float: left;
    }
    .nav-list ul li {
        float: left;
    }
    .nav-list ul:nth-child(2) {
        float: right;
    }
    .nav-list ul li.hidden {
        display: none;
    }
}

@media screen and (min-width: 992px) {
    .container {
        width: 970px;
    }
    .nav-header h2 {
        display: block;
    }
    .clearfix::after {
        clear: none;
    }
}

@media screen and (min-width: 1200px) {
    .container {
        width: 1170px;
    }
    .nav-list ul li.hidden {
        display: block;
    }
 }